Why are there not that many recoil operated military rifles?
- Thread starter Carter
- Start date
- Status
kbar-04
Member
I own one of the semi FAMAS rifles and Ive shot the real deal ones in my liaison duties in the past. It is a delayed blowback for sure with a fluted chamber similar to the HK. It uses a delay lever instead of locking rollers though. The French are very satisfied with the FAMAS and have used it for 30 years now. Adopted in 1977 but not fielded until 1979-1980. It is a very robust rifle and far handier than its appearance would suggest.
Looking through a number of my firearms references, they all differentiate between blowback and recoil operation (locked versus unlocked action at the moment of firing)
BTW. the Barrett M82 is another recoil operated weapon that is not a machinegun and in use. True, it is typically classed and an anti-material rifle.
What does Chinn have to say about blowback versus recoil operation? I call that an authoritative source. Weeks and Hoggs definitely distinguished between blowback and recoil operation, as do most other technical authorities.
Of course if you really want to get technical, you could argue that most gas operated rifles are actually gas unlocked, blowback operated gun, since a large percentage of these gun actually use residual pressure to drive the bolt back. The gas system merely unlocks the bolt after pressure has dropped to a safe level.
IIRC, the FAMAS uses a modified form of Kiraly's delayed blowback. I haven't looked at the bolt of a FAMAS in years, but perhaps KBar would be king enough to post a pic.
Gryffydd, the French Foreign Legion has seen more 'real combat' than most armies, and they seem pretty happy with the FAMAS.
BTW. the Barrett M82 is another recoil operated weapon that is not a machinegun and in use. True, it is typically classed and an anti-material rifle.
What does Chinn have to say about blowback versus recoil operation? I call that an authoritative source. Weeks and Hoggs definitely distinguished between blowback and recoil operation, as do most other technical authorities.
Of course if you really want to get technical, you could argue that most gas operated rifles are actually gas unlocked, blowback operated gun, since a large percentage of these gun actually use residual pressure to drive the bolt back. The gas system merely unlocks the bolt after pressure has dropped to a safe level.
IIRC, the FAMAS uses a modified form of Kiraly's delayed blowback. I haven't looked at the bolt of a FAMAS in years, but perhaps KBar would be king enough to post a pic.
Gryffydd, the French Foreign Legion has seen more 'real combat' than most armies, and they seem pretty happy with the FAMAS.
Some further thoughts on recoil vs blowback and why they are two different systems.
In blowback systems, the cartridge case operates essentially like a piston. Gas pressure moved the slide backwards via the breech face in the same manner that a hydraulic jack lifts a car. Recoil operation, by contrast relies on Newton's third law.
A simple way to illustrate this is to imagine a blowback and a recoil operated firearm, each with the bullet fixed so that it cannot travel down the barrel. ignoring the obvious dangerous pressure, a blow back operated firearm would still cycle even if the bullet was fixed, because the cartridge case could act as a piston against the breech face.
In a recoil operated gun, the action cannot operate unless the projectile can move, because there is no reaction against the bullets forward travel (action). This is why you can make a blowback gun operate with blanks by plugging the muzzle, while a recoil operated gun will not function with blanks if the barrel is occluded.
Two completely different physical principles - Newtonian action/reaction versus expanding gas operating on a piston.
In blowback systems, the cartridge case operates essentially like a piston. Gas pressure moved the slide backwards via the breech face in the same manner that a hydraulic jack lifts a car. Recoil operation, by contrast relies on Newton's third law.
A simple way to illustrate this is to imagine a blowback and a recoil operated firearm, each with the bullet fixed so that it cannot travel down the barrel. ignoring the obvious dangerous pressure, a blow back operated firearm would still cycle even if the bullet was fixed, because the cartridge case could act as a piston against the breech face.
In a recoil operated gun, the action cannot operate unless the projectile can move, because there is no reaction against the bullets forward travel (action). This is why you can make a blowback gun operate with blanks by plugging the muzzle, while a recoil operated gun will not function with blanks if the barrel is occluded.
Two completely different physical principles - Newtonian action/reaction versus expanding gas operating on a piston.
General Geoff
Member
A recoil operated gun simply has a barrel that is initially locked with the bolt; this entire locked barrel/bolt assembly acts as an inertia damper, whereas just the bolt acts as the inertia damper in a straight blowback design (at least until the bolt reaches the end of its travel, whereupon it imparts its energy to the frame). With a "fixed" projectile, that projectile then ALSO becomes a part of the barrel/bolt assembly in a recoil operated firearm, and the expanding gases have nowhere to go.
Blowback operation also relies on this. With a plugged barrel, the barrel/frame assembly then acts as the projectile would, in terms of trapping the expanding gas so that it exerts equal pressure on both the bolt, and the barrel/frame assembly.
- Status
